Quantum diffusion and catalyzed conversion of ortho-H-2 molecules in solidhydrogen

The ortho-para conversion in solid hydrogen catalyzed by a small amount (si milar to 10(-3)) of OZ impurities was studied to determine the temperature and concentration dependence of the ortho-H-2 diffusion coefficient. For T> 5 K the diffusion coefficient has the activation-type dependence on tempera ture D(T) = 2 x 10(-11) exp(-92/T) cm(2) s(-1) and is independent of the or tho-Hz concentration C. For T<4 K this coefficient substantially changes it s behavior and far C in the range 0.02-0.75 it can be described by the rela tion D(T,C) = 1 x 10(-21). T/C cm(2) s(-1). The results obtained are interp reted in terms of the quantum diffusion of ortho-H-2 molecules in sold hydr ogen.